Using reflectance (R) and photoluminescence (PL) measurements InGaN/GaN multiple-quantum-well (MQW) structures embedded in an asymmetric microcavity with different thickness of stacking pairs have been studied. The asymmetric microcavity structures are composed of a cavity sandwitched between the air/semiconductor interface and a mirror using distributed Bragg reflector (DBR). For the DBR with thinner A1N layers the high-reflectivity stop band locates at higher photon energy. The luminescence efficiency and the spectrum of InGaN/GaN multiple-quantum-well structures will be modified by the microcavity. A comparison of PL with R spectra shows that the emission efficiency can be enhanced by matching up the luminescence spectrum coming from the MQW and the high-reflectivity stop band. From the blue shift of the cavity modes as a function of incident angles the refractive index and cavity length can be determined. By measuring the PL spectra as a function of emission angle, it is found that the PL spectra were predominatly determined by microcavity resonances.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics